Proposed classification of auriculotemporal nerve, based on the root system

The topography of the auriculotemporal nerve (ATN) root system is the main criterion of this nerve classification. Previous publications indicate that ATN may have between one and five roots. Most common is a one- or two-root variant of the nerve structure. The problem of many publications is the inconsistency of nomenclature which concerns the terms “roots”, “connecting branches”, or “branches” that are used to identify the same structures. This study was performed on 80 specimens (40 adults and 40 fetuses) to propose a classification based on: (i) the number of roots, (ii) way of root division, and (iii) configuration of interradicular fibers that form the ATN trunk. This new classification is a remedy for inconsistency of nomenclature of ATN in the infratemporal fossa. This classification system has proven beneficial when organizing all ATN variants described in previous studies and could become a helpful tool for surgeons and dentists. Examination of ATN from the infratemporal fossa of fetuses (the youngest was at 18 weeks gestational age) showed that, at that stage, the nerve is fully developed.

Medial meniscus anatomy-from basic science to treatment

This paper focuses on the anatomical attachment of the medial meniscus. Detailed anatomical dissections have been performed and illustrated. Five zones can be distinguished in regard to the meniscus attachments anatomy: zone 1 (of the anterior root), zone 2 (anteromedial zone), zone 3 (the medial zone), zone 4 (the posterior zone) and the zone 5 (of the posterior root). The understanding of the meniscal anatomy is especially crucial for meniscus repair but also for correct fixation of the anterior and posterior horn of the medial meniscus.

Ribbon like appearance of the midsubstance fibres of the anterior cruciate ligament close to its femoral insertion site: a cadaveric study including 111 knees

PURPOSE

Recently, the configuration of the anterior cruciate ligament (ACL) from its direct femoral insertion to midsubstance was found to be flat. This might have an important impact for anatomical ACL reconstruction. The purpose of this anatomical study was to evaluate the macroscopic appearance of the ACL from femoral to midsubstance.

METHODS

The ACL was dissected in 111 human fresh frozen cadaver knees from its femoral insertion to midsubstance, and the shape was described. The anatomical findings were documented on digital photographs and on video. Thirty knees were sent for computed tomography (CT), magnetic resonance imaging (MRI) and histology of the femoral ACL insertion.

RESULTS

Two millimetres from its direct femoral insertion, the ACL fibres formed a flat ribbon in all dissected knees without a clear separation between AM and PL bundles. The ribbon was in exact continuity of the posterior femoral cortex. The width of the ribbon was between 11.43 and 16.18 mm and the thickness of the ACL was only 2.54-3.38 mm. 3D CT, MRI and the histological examination confirmed above findings.

CONCLUSION

This is a detailed anatomical study describing the ribbon-like structure of the ACL from its femoral insertion to midsubstance. A key point was to carefully remove the surface fibrous membrane of the ACL. A total of 2-3 mm from its bony femoral insertion, the ACL formed a flat ribbon without a clear separation between AM and PL bundles. The ribbon was in exact continuity of the posterior femoral cortex. The findings of a flat ligament may change the future approach to femoral ACL footprint and midsubstance ACL reconstruction and to graft selection.

Cardiac mouse lymphatics: developmental and anatomical update

The adult mouse heart possesses an extensive lymphatic plexus draining predominantly the subepicardium and the outer layer of the myocardial wall. However, the development of this plexus has not been entirely explored, partially because of the lack of suitable methods for its visualization as well as prolonged lymphatic vessel formation that starts prenatally and proceeds during postnatal stages. Also, neither the course nor location of collecting vessels draining lymph from the mouse heart have been precisely characterized. In this article, we report that murine cardiac lymphatic plexus development that is limited prenatally only to the subepicardial area, postnatally proceeds from the subepicardium toward the myocardial wall with the base-to-apex gradient; this plexus eventually reaches the outer half of the myocardium with a predominant location around branches of coronary arteries and veins. Based on multiple marker immunostaining, the molecular marker-phenotype of cardiac lymphatic endothelial cells can be characterized as: Prox-1(+), Lyve-1(+), VEGFR3(+), Podoplanin(+), VEGFR2(+), CD144(+), Tie2(+), CD31(+), vWF(-), CD34(-), CD133(-). There are two major collecting vessels: one draining the right and left ventricles along the left conal vein and running upwards to the left side of the pulmonary trunk and further to the nearest lymph nodes (under the aortic arch and near the trachea), and the other one with its major branch running along the left cardiac vein and further on the surface of the coronary sinus and the left atrium to paratracheal lymph nodes. The extracardiac collectors gain the smooth muscle cell layer during late postnatal stages.

Arteries of the anterior wall of the maxilla in sinus lift surgery

Knowledge of the anatomical course of the anterior maxillary wall and alveolar process arteries is essential for sinus lift procedures. The aim of this study was to analyse the localization of anastomoses between the infraorbital and posterior superior alveolar artery on 101 computed tomography (CT) scans of maxillary sinuses (patients aged 18-70 years). The distance from the anastomosis to the bone point was measured on CT scans for each tooth location; for edentulous patients measurements were made to the lower edge of the alveolar process, and for dentate patients to the neck of the tooth. Measurements were done independently by two observers. The anastomosis analysed was identified on 50% of CT scans. The distance to the anastomosis was longest above the premolar (20.4 mm from tooth cervical line) and shortest above the first molar (15.9 mm to the edge of the alveolar process). The anastomosis can be localized on a CT scan for exact positioning of the antrotomy in 50% of patients. For the remaining patients, the anatomical information provided in this study can be used to reduce the risk of damage to the anastomosis. This study provides information on the distance from the anastomosis to the neck of preserved teeth in partially edentulous patients, which can be used as a reference point during sinus lift procedures.

How does Adamkiewicz artery influence blood supply to the fetal spinal cord?

Adamkiewicz artery became important in clinical practice since it was noticed that its damage during aorta aneurysm repair surgery can sometimes lead to distal spinal cord ischemia. The complexity of anatomical variations can be related to the development of spinal cord arteries. The aim was to describe topography of Adamkiewicz artery and its relations to the anterior spinal artery in fetuses. The study was carried on 4 Batson's resin corrosion casts and 24 formalin-fixed fetuses injected with dyed gelatin or latex aged 15-24 weeks gestational age. In fixed specimens vertebral canals were dissected, the anterior spinal artery was traced and Adamkiewicz artery localized. Arteries were photographed and digitally measured. Data were afterwards statistically analyzed. Anterior spinal artery was duplicated in 3/28 cases. There were from 1 to 3 Adamkiewicz arteries per specimen, mean 1.71. No relation was found between the number of Adamkiewicz artery and age. In 37/48 cases Adamkiewicz artery emptied into the anterior spinal artery on the left side. Mean degree of narrowing in anterior spinal artery (diameter of the anterior spinal artery above junction with Adamkiewicz artery divided by its diameter under that junction) was 76.74%. The diameter of Adamkiewicz artery was also correlated linearly with the degree of narrowing of anterior spinal artery (r=0.68; p<0.05). The arteries of the anterior aspect of thoracolumbar spinal cord in the 2nd trimester of pregnancy represent the adult pattern. A potentially great impact of Adamkiewicz artery on the distal spinal cord circulation may be postulated on the basis of these morphological data.

Critical Pressure for Arterial Wall Rupture in Major Human Cerebral Arteries

Background and Purpose—

Intracranial bleeding is linked to hemodynamic stress factors, such as hypertension. However, there are no studies that tested the breaking pressure of normal large cerebral arteries in humans.

Methods—

The brains of 10 cadavers (age, 47±14 years; 9 men) were harvested within 48 hours postmortem for 31 segments of the main intracranial arteries. After careful microsurgical preparation, the vessels were pressurized with saline and observed until they ruptured.

Results—

Vessel diameters averaged 2.6±0.3 mm (range, 1.2–4.3 mm). The average rupture pressure was 2.21±0.59 atm (range, 1.13–4.3 atm) and decreased with age at −0.025 atm/y ( R 2 =40%; P <0.0002). The maximum diameter distention at rupture was 30±9% (13%–52%), which also decreased with age (−0.5%/y; R 2 =78%; P <0.00001). Neither the rupture pressure nor the maximum distention showed significant dependence on the resting vessel diameter. No significant dependencies were found on the vessel origin, vascular configuration, direction of the rupture, or the presence of minor coexisting pathology.

Conclusions—

Human cerebral arterial wall breaks only at extremely high intravascular pressures, exceeding several times the highest observed systolic blood pressure, even accounting for age trends. Systolic hypertension alone may not be sufficient to cause intracranial hemorrhage, and there may be additional contributing factors.

Can palmar creases serve as landmarks for the deeper neuro-vascular structures?

PURPOSE

The aim of this study was the examination of the superficial anatomy of palmar creases and their relation to deeper neuro-vascular structures.

METHODS

Four creases: distal wrist flexion crease, thenar crease, proximal palmar crease and distal palmar crease were evaluated with reference to the following structures: palmar cutaneous branch of median nerve, palmar cutaneous branch of ulnar nerve, the nerve of Henle, transverse palmar branches from ulnar nerve, recurrent motor branch of median nerve, radial proper palmar digital nerve to the index and the ulnar proper palmar digital nerve to the thumb, Berrettini's communicating branch, ulnar nerve and artery, superficial palmar arch. We performed dissections of 20 cadaveric upper limbs derived from a homogenous Caucasian group. In our study we measured the location of surgically important structures with reference to palmar skin creases.

RESULTS

Among the other observations we noticed that the palmar cutaneous branches of the median and ulnar nerves were located at least 0.5 cm away from the thenar crease. The superficial palmar arch was found between the thenar and proximal palmar crease and never crossed the proximal or distal palmar creases.

CONCLUSIONS

These anatomical dissections will provide reference material for further ultrasound studies on the arrangements of neuro-vascular structures in reference to superficial palmar creases.

Distinct strategies in the treatment of epidural hematoma in children: clinical considerations

BACKGROUND

Epidural hematoma (EDH) is the most common form of intracranial bleeding following head trauma in pediatric patients. It may develop into a life-threatening pathology, requiring an immediate neurosurgical intervention. However, due to an increasing number of posttrauma CT scans most pediatric EDH patients can be treated conservatively, because of minor dimensions of the clot and the possibility of quick control scanning.

AIM

Evaluation of distinct strategies in the treatment of EDH patients in our department between January 2007 and December 2012.

RESULTS

During this period a total number of 221 patients with EDH were enrolled in the study. Seventy-seven of them (35%) underwent surgical procedures. One hundred and forty-four patients (65%) were treated conservatively. The dominating age group among nonsurgical patients was 0-4 years (85 cases, 61% of the nonsurgical group). In most of these cases a small epidural blood collection with inconsiderable dynamics was observed. Twenty-one patients from this age group (20%) were treated operatively. Among older children (5-18 years) surgical treatment was implemented in 56 (49%) cases.

CONCLUSIONS

(1) EDH may be successfully treated conservatively with the use of control CT scans. (2) Smaller blood clots dominate in younger patients. (3) Surgical intervention is required more commonly in older patients.

Clinical anatomy of the auriculotemporal nerve in the area of the infratemporal fossa

The auriculotemporal nerve is a sensory branch extending from the posterior section of the mandibular nerve trunk. Its nerve roots form a short trunk, which gives off a number of branches, innervating: the temporomandibular joint, the temporal region, structures of the external ear: auricle, and external acoustic meatus, and the parotid gland. It also conducts excretory fibres to the buccal and labial glands. Anatomical relationships between the auriculotemporal nerve and the muscles of mastication, temporomandibular joint, and surrounding vessels in the area of the infratemporal fossa create favourable conditions for entrapment syndromes. Entrapment of the auriculotemporal nerve plays a role in the pathogenesis of temporomandibular joint pain syndromes, headaches, as well as pain symptoms or paraesthesias within the external acoustic meatus and auricle. The current study was performed on 16 specimens containing the infratemporal fossa. Some variations in the nerve roots of the auriculotemporal nerve were found and described as one-, two-, three-, four-, and five-root variants. The topography of the auriculotemporal nerve and its close relationship to the structures of the temporomandibular joint were described. Individually, the variable topography of the nerve course may play a role in the symptomatology of headaches and localisation of pain in the face regions and masticatory system.

Anatomy of the medial femoral circumflex artery with respect to the vascularity of the femoral head

We performed a series of 16 anatomical dissections on Caucasian cadaver material to determine the surgical anatomy of the medial femoral circumflex artery (MFCA) and its anastomoses. These confirmed that the femoral head receives its blood supply primarily from the MFCA via a group of posterior superior nutrient arteries and the posterior inferior nutrient artery. In terms of anastomoses that may also contribute to the blood supply, the anastomosis with the inferior gluteal artery, via the piriformis branch, is the most important. These dissections provide a base of knowledge for further radiological studies on the vascularity of the normal femoral head and its vascularity after dislocation of the hip.

Median aperture of the fourth ventricle revisited

BACKGROUND

The median aperture of Magendie is the largest of three openings of the fourth ventricle and thus it forms the main path for the outflow of the cerebrospinal fluid from the ventricle. The Magendie aperture connects the fourth ventricle with the cisterna magna and makes a natural corridor for neurosurgical approach and inspection of the ventricle and its floor. The purpose of this study was to give a contemporary anatomical view of this structure in the context of historical data.

MATERIAL AND METHODS

The Magendie foramen was studied in 30 fixed specimens of human brainstems with cerebella. The microdissection technique was used. Measurements were taken with a microscope ocular ruler.

RESULTS

The aperture is limited by the following structures: obex and gracile tubercles inferiorly, and tela choroidea with choroid plexus superolaterally. Obex tubercles usually have the form of a piece of neural tissue bridging two halves of the brainstem above the entrance to the central canal. Gracile tubercles together are 8.15 mm wide and the maximal width of the foramen is 6.53 mm. Tela choroidea attaches laterally at both sides to the inferior medullary velum. In most cases the right and left choroid plexus are connected to each other with a triangular membrane of tela choroidea, which protrudes through the median foramen and attaches to the vermis at a highly variable level.

CONCLUSIONS

We hope that the presented description of anatomical relations around the Magendie aperture, with its new measurements, will be helpful for those operating in the area and will explain some of the inaccuracies found in literature.

Radiological anatomy of the ambient cistern in children

Ambient cistern (AC) is a thin extension of the subarachnoid space surrounding the brainstem at the level of the mesencephalon and pons. Despite various definitions, it constitutes an important landmark in clinical assessment of intracranial volume reserve. Although it is indisputably useful, there exists no defined standard for radiological examination for the dimensions and ranges in specific age groups. This paper aims to describe the ambient cistern anatomically and give the ranges of dimensions for proper radiological interpretation. The study was performed on 160 axial computed tomography (CT) examinations of Polish children of both sexes, aged 1-18 years, admitted to the hospital because of mild brain concussion. Pictures were made using a Siemens 8-row CT scanner, without contrast administration. We estimated distances at the level of the pons and midbrain, based on axial cross-sections, according to standard radiological protocol. The parameters included the width of the AC in its anterior and posterior part, the width of the tentorial notch, and the distance from the pons and sella. All measurements were analyzed statistically with StatSoft Statistica 8.0 software. The average width of the AC differs between age groups. It is greatest at 1-3 years (2.8 +/- 0.6 mm) and lowest at 4-10 years (2.4 +/- 0.6 mm). AC is more likely to be greater in its anterior part in boys. The distance from the sella to the pons is greatest in 1-3-year-old girls (6.9 +/- 1.3 mm), and the tentorial notch is widest in the 15-18-year-old group (24.6 +/- 2.4 mm). Dimensions of the AC correlate with intracranial reserve volume. This is particularly visible in the youngest children. Thin and narrow AC is not always a sign of raised intracranial pressure. It may be specific for the child's age.

[Relationship between heart development and pathogenesis of congenital heart defects in current literature]

This work presents current ideas on embryonic heart development and is an attempt to elucidate pathogenesis of congenital heart defects. The heart develops from 2 areas, the so-called "heart fields", which differ in the expression of various genes and in sensitivity to certain substances (for example retinoid acid). Heart fields are the source of cardiomyocytes and endocardial endothelial cells for the developing heart tube. Neural crest cells attaining the heart take part in the formation of tunica media of great vessels and the aorto-pulmonary septum. An interaction between the cells of the secondary heart field and neural crest cells migrating to the heart plays a significant role in heart development. This interaction is accomplished by various mediators released into the cell environment (e.g. activation of Notch, which induces secretion of growth factors such as Fgf8). Disturbances in signaling between these cellular populations lead to malformations of the cardiac outflow tract. The sinus venosus is the source of endothelial cells of the coronary vasculature, whereas the proepicardium provides cells for the epicardium, smooth muscle cells and fibroblasts.

Image-guided dissection of human white matter tracts as a new method of modern neuroanatomical training

Neuronavigation is a kind of image-guided surgery used during neurosurgical procedures. Based on specific equipment which is compatible with the software calculating and processing the patient's data; this method allows the determination of the location of anatomical structures and visualisation of surgical instruments in the operative field. Although standard brain dissection is still the best method of neuroanatomical training, some limitations occur. The most important of these is the inability of conversion from three-dimensional (3D) view to flat pictures of the brain structures, as viewed on computed tomography (CT) and magnetic resonance imaging (MRI), being essential in neuroanatomical training nowadays. The aim of the study was the implementation of a neuronavigating system for brain anatomy training purposes. The study was performed on 10 human brain hemispheres, dissected due to classical methods (standard brain anatomical sections, stepwise ventricular system opening and partial dissection of white matter tracts using Klingler's dissection technique). The material was scanned in a 1.5 T magnetic resonance scanner using a modified neuronavigation protocol. The brains were prepared before dissection as proposed by Klingler. The subsequent steps of the dissection were documented with a digital camera. The progress of the dissection was visualised using the neuronavigation system (Medtronic Stealth Station Treon) with cranial application software. In the course of the study, numerous 3D and 2D images were obtained. The images were related to each other and linked anatomical structures in the specimen with their appearance on CT and MRI scans. The implementation of a neuronavigation system for brain structures dissection facilitates visualization and understanding of their proper location. This new method offers a constant and precise orientation and simplifies understanding of the relation of the 3D view of a specimen to that of the 2D image.

The study of arterial anastomoses in the region of the alveolar process and the anterior maxilla wall in foetuses

The anterior maxilla wall and alveolar process are covered by the arterial network. Procedures in this region can cause heavy bleeding. Knowledge of the anatomical course of a particular artery is essential for performing surgery in this area. The aim of this study was to search for and then analyse anastomoses between the infraorbital and posterior superior alveolar artery. In the study, 19 maxillas of foetuses were analysed. The arteries were injected with coloured latex. The dissection was carried out using a surgical microscope and microsurgical equipment. The lower eyelid with cheek skin was separated and the facial muscles were cut to expose the maxilla and arteries of the alveolar process. The study revealed that in 10 out of 19 of the specimens there was an arterial connection between the infraorbital and posterior superior alveolar artery. The course of the analysed anastomosis was diverse. In all cases we observed an anterior superior alveolar artery. In all specimens the alveolar process was vascularised by many arteries originating from the analysed anastomosis. The location of the analysed anastomosis can be stated before operation, on the line between the medial eye angle and the sixth tooth of the same side. The anastomosis described in the study means that caudally running arteries are important in choosing incisions in procedures performed at the alveolar process.

Anatomy of the posterior cruciate ligament

The purpose of the study was to explain the architecture of the posterior cruciate ligament because the views on its structure presented in the literature are inconsistent - from those considering it as indivisible to those presenting it as a multifascicular structure. Twenty formalin-fixed ligaments from human knee joints were tested using the preparation technique. All posterior cruciate ligaments clearly divided into the anterolateral bundle and the posteromedial bundle (20/20). In all ligaments, 2 fascicles were identified in the posteromedial bundle (20/20). In most cases, 2 fascicles were also seen in the anterolateral bundle (14/20). Less commonly, it consisted of multiple fascicles (6/20).

The anatomy of the fundic branches of the stomach: preliminary results

The fundic branches of the stomach can be defined as a group of vessels that can arise either directly or indirectly from the following source arteries: the left inferior phrenic artery, the accessory left hepatic artery, the left gastric artery, the left middle suprarenal artery, the main trunk of the splenic artery, the posterior gastric artery, the superior polar artery, the gastrosplenic artery, the left gastroepiploic artery and the splenic artery with its inferior and superior terminal branches. It is worth mentioning that the fundic branches of the left gastroepiploic artery and the superior and inferior terminal branches of the splenic artery, like other vessels arising from these three source arteries and supplying the stomach, are defined as short gastric arteries. The anatomy of these fundic branches, particularly relevant to some surgical procedures, is not sufficiently described, and the current literature suffers from lack of publications on this particular topic. We therefore decided to explore in detail the arterial vascularisation of the gastric fundus. The research was carried out on material consisting of 15 human stomach specimens. The anatomical analysis comprised the following: the number of occurrences of fundic branches in each of the source arteries defined above, the distance between the origins of the source artery and its arising fundic branch, the way in which the fundic branches arose, the length, diameter at point of origin and morphology of the fundic branches, as well as the exact point of perforation of each fundic branch on the fundus. The highest incidence of the direct-branching pattern of fundic branches was in the left middle suprarenal artery, the gastrosplenic artery and the left gastrosplenic artery. The accessory left hepatic artery, the left gastric artery and the main trunk of the splenic artery were the most frequent site of the indirectly arising pattern of fundic branch. The highest median value of fundic branch length was 63.05 mm, found in the accessory left hepatic artery group. The largest median diameter value of the vessel was encountered among those originating in the left middle suprarenal artery and reached 2.17 mm. The posterolateral quadrant of the fundus received the largest number of fundic branches, amounting to 46.5% of all the fundic branches studied.